Air assist atomization of the liquid fuel emitted from the tip end of a fuel injector is a known technique that is used to promote better preparation of the combustible air/fuel mixture that is introduced into the combustion chambers of an internal combustion engine. A better mixture preparation promotes both a cleaner and a more efficient combustion process, a desirable goal from the standpoint of both exhaust emissions and fuel economy.
The state of the art contains a substantial number of patents relating to air assist atomization technology. The technology recognizes the benefits that can be gained by the inclusion of special assist air passages that direct the assist air into interaction with the injected liquid fuel. Certain air assist fuel injection systems use pressurized air, from either a pump or some other source of pressurization, as the assist air. Other systems rely on the pressure differential that exists between the atmosphere and the engine's induction system during certain conditions of engine operation. It is a common technique to mount the fuel injectors in an engine manifold or fuel rail which is constructed to include assist air passages for delivering the assist air to the individual injectors.
Insofar as the applicant is aware from preliminary novelty searching of the present invention, the practices of the prior art for defining the final length of the assist air passage to the injector tip involve the use of either special fuel injectors or special fuel rail or manifold assemblies to cooperatively define the final length of the passage, or else the addition of a single part that either per se or in cooperation with the adjacent structure provides the definition. The following U.S. patents which were developed in preliminary novelty searching are typical of these practices: 3,656,693; 4,046,121; 4,519,370; and 4,945,877.
The present invention relates to novel air assist atomizers in which the definition of the final length of the assist air passage to each fuel injector tip is provided by the cooperative organization and arrangement of two additional parts which form an atomizer assembly disposed between the tip end of an injector and the wall of a socket that receives the injector. One advantage of the present invention is that it adapts an otherwise conventional electrically-operated fuel injector for use in an air assist system without the need to make modifications to the basic injector, and without the need to make special accommodations in the injector-receiving socket other than suitably dimensioning the socket to accept the atomizer assembly on the tip end of the injector. Another advantage of the invention is the ability to configure the final length of the air assist passage to an injector in any of a number of different ways. Certain of these configurations possess their own individually unique attributes, as will be seen in the ensuing detailed description of each of a number of different embodiments of the invention. The drawings which accompany this disclosure illustrate presently preferred embodiments of the invention according to the best mode contemplated at the present time in carrying out the invention.